The nucleotide sequence of a HMW glutenin subunit gene located on chromosome 1A of wheat (Triticum aestivumL.)

Abstract

A cloned 8.2 kb EcoRI fragment has been isolated from a genomic library of DNA derived from Triticum aestivum L. cv. Cheyenne. This fragment contains sequences related to the high molecular weight (HMW) subunits of glutenin, proteins considered to be important in determining the elastic properties of gluten. The cloned HMW subunit gene appears to be derived from chromosome 1A. The nucleotide sequence of this gene has provided new information on the structure and evolution of the HMW subunits. However, hybrid-selection translation experiments suggest that this gene is silent.

Polymorphism and genetic control of high molecular weight glutenin subunits in wild tetraploid wheat Triticum turgidum var. dicoccoides

“…It is assumed that in patterns in which lAy subunit was not expressed, the gene coding for it was present but inactive, as found in cultivated wheats (Thompson eta!., 1985;Forde et a!., 1985). Thus, the number of different HMW glutenin genes in each genome seems to be only two-one coding for the x and the other for the y group.…”

“…The phenomenon could also result from differential splicing of introns in the mRNA of the gene controlling iBy, as reported for other genes (Rozek and Davidson, 1986). Yet, recently an alpha gliadin gene was shown not to include introns (Anderson et a!., 1984), and isolated HMW glutenin genes were shown to be devoid of introns (Forde et a!., 1985;Thompson eta!., 1985;Sugiyama et a!., 1985). iBy' might also result from an in vivo, or an in vitro (during the extraction process) proteolytic digestion of the iBy subunit, as was found in wheat-leaf-protein sub- The HMW glutenins encoded by the A genome have been studied to a much lesser extent, their genes not being usually expressed in cultivated wheats (Galili and Feldman, 1983c;Forde et a!., 1985).…”

High molecular weight glutenin subunit variation in the Sitopsis section of Aegilops. Implications for the origin of the B genome of wheat

“…Generally, in all species studied, these clusters contain two genes, namely x controlling the subunit that shows the slower electrophoretic mobility and y controlling the subumit with faster electrophoretic mobility (Forde et a!., 1985;Harberd et a!., 1986;Waines and Payne, 1987). In some cases, two or more bands were observed for the faster moving zone.…”

The prolamin storage proteins of cereal seeds: structure and evolution

“…Their amino acid compositions (Table 2) [39] are characterized by high contents of glycine (14-19 mol %), glutamine (37-39 mol %) and proline (12-14 mol%). Genes for seven different HMW subunits have been isolated and the amino acid sequences of the encoded proteins deduced [40][41][42][43][44][45][46][47]. The proteins vary in length from 627 to 827 residues, with true Mr values of 67500 to 88 128.…”